Effect of St John's wort dose and preparations on the pharmacokinetics of digoxin.

Background And Objective: St John's wort preparations vary in composition, main constituents, formulation, and daily dose administered. The aim of the study was to evaluate the possible pharmacokinetic interaction of marketed St John's wort formulations and doses with digoxin.

Methods: A randomized, placebo-controlled, parallel-group study was performed in 96 healthy volunteers in 3 study parts.